Answer
(a) physical
(b) physical
(c) chemical
(d) chemical
Work Step by Step
(a) physical
This is an example of a physical change because there is no chemical reaction occurring.
(b) physical
This is an example of a physical change because breaking glass does not change what the substance is.
(c) chemical
This is an example of a chemical change because when leaves change color, all sorts of chemical changes are occurring within the leaf.
(d) chemical
This is an example of a chemical change because iron is reacting with oxygen in the air to form iron oxide.